US20030018341A1 - Targeting apparatus for use in performing endofemoral osteotomy surgery - Google Patents

Abstract

Targeting apparatus for use in performing endofemoral osteotomy surgery comprising a support element provided with a drill guide, means for securing a support element to the proximal end of a prosthesis to be implanted and which include a proximal location element which is shaped to extend around the great trochanter and muscles of the femur in which the implant is to be located, and means for adjusting the angular position of the drill guide in relation to the femur about a proximal-distal axis.

Description

BACKGROUND OF THE INVENTION
• This invention relates to a targeting apparatus for use in performing endofemoral osteotomy surgery. The apparatus is also suitable for conversion so that it can be used in transfemoral osteotomy surgery. In this particular surgical technique the femur is exposed along a proximal-distal line, the soft tissue (skin, muscle) being folded back on each side to expose the bone. The proximal end of the femur is now opened as a “window” and a femoral prosthesis is inserted into the bone canal.[0001]
• As mentioned above, the present invention is capable of being used with both surgical approaches if converted.[0002]
• There are difficulties in both techniques in assessing the particular angular position of the prosthesis in the femoral canal and the exact location of the resectioning of the femur must be accurately judged. A further difficulty arises with regard to the placement of one or more retaining bolts towards the distal end of the stem of the prosthesis. These bolts or pins pass through the bone, the stem of prosthesis and out through the other side of the bone thus anchoring the prosthesis in position. It is difficult for surgeons to judge the exact position to drill the holes in the bone to coincide with the holes in the implant and it is also necessary to select the correct angular position of the prosthesis and therefore the holes. It is also difficult for the surgeon to judge the exact distance down the femur for the holes to achieve the correct leg length of the correction.[0003]
• The present invention is intended to overcome some of the difficulties referred to above and to provide apparatus which will achieve a more accurate surgical technique.[0004]
SUMMARY OF THE INVENTION
• According to the present invention targeting apparatus for use in performing endofemoral osteotomy surgery comprises a support element provided with a drill guide, a connector for securing the support element to the proximal end of the prosthesis to be implanted and which include a proximal location element which is shaped to extend around the great trochanter and muscles of the femur in which the implant is to be located, and an adjustor for adjusting the angular position of the drill guide in relation to the femur about a proximal-distal axis.[0005]
• Thus, the apparatus can be used to accurately locate the angular position of the drill guide and the prosthesis (anteversion setting) and which can be used to drill the holes to take the retaining bolt or bolts in the bone.[0006]
• Preferably the proximal location element is in the form of a curved arm connected to the support element and this arm can be substantially S-shaped.[0007]
• The proximal location element can be arranged to be detachable from the support element, for example, by use of a plug and socket connection, and this can be of a triangular cross-section.[0008]
• Two detachable alternative proximal location elements can be provided, one for use with a right femur and the other for use with a left femur.[0009]
• The targeting apparatus according to the invention can also be used for performing transfemoral osteotomy surgery by the provision of suitable conversion features. Thus, the apparatus can include conversion means for converting it for use in performing transfemoral osteotomy surgery.[0010]
• The conversion means can include a connector for securing the support element to a resectioned femur to allow this form of surgery to be carried out.[0011]
• Alternative devices are also provided for securing the support element to the prosthesis to be implanted and which is adapted to replace the shaped proximal location element.[0012]
• This alternative device may comprise a substantially straight proximal arm adapted for connection to the support element.[0013]
• When converted in this way the apparatus can embody the features set forth in British Patent Application Nos. 00 27698.0 filed Nov. 13, 2000, 00 27700.4 filed Nov. 13, 2000 and 01 05779.3 filed Mar. 8, 2001.[0014]
• The invention also includes a kit of parts to provide targeting apparatus for use in performing endofemoral and/or transfemoral osteotomy surgery comprising a support element provided with a drill guide, a connector for securing the support element to a prosthesis to be implanted when performing endofemoral surgery and which includes a proximal location element which is shaped to extend around the great trochanter and muscles of the femur, alternative connectors for securing the support element to a prosthesis to be implanted when performing transfemoral surgery, an adjuster for adjusting the angular position of the drill guide in relation to the resectioned femur about a proximal/distal axis, and a connector for securing the support element to a femur.[0015]
• The kit of parts can also include a drill guide element which has a line of drill guide openings each of which is adapted to guide a drill and a connector for rigidly securing the drill guide element to the connector for securing the support element to a femur.[0016]
• Also included in the kit of parts can be a drill guide for drilling openings through the bone and soft tissue when it has been folded back into position at the proximal end of the femur when conducting the transfemoral surgery.[0017]
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention can be performed in various ways and some embodiments will now be described by way of example and with reference to the accompanying drawings in which:[0018]
• FIG. 1 is an isometric view from above showing the layout of the targeting device according to the present invention when set up for use in performing endofemoral osteotomy surgery;[0019]
• FIG. 2 is an isometric view from a first side of part of the apparatus shown in FIG. 1;[0020]
• FIG. 3 is an isometric view of part of the apparatus from the side opposite that shown in FIG. 2;[0021]
• FIG. 4 is a diagrammatic side view of a femur showing how it is cut for performing transfemoral osteotomy surgery;[0022]
• FIG. 5 is a diagrammatic perspective view showing how the “window” is formed in the femur for transfemoral osteotomy surgery;[0023]
• FIG. 6 is an isometric view from above of the apparatus shown in FIG. 1 when converted for use when performing transfemoral osteotomy surgery and in position on the femur;[0024]
• FIG. 7 is an isometric view from above showing part of the apparatus shown in FIG. 6 with the proximal location element detached;[0025]
• FIG. 8 is a part cross-sectional view of the connector for securing the support element of the apparatus shown in the preceding figures to a prosthesis to be implanted;[0026]
• FIG. 9 is a side elevation of a clamp device shown in FIG. 6 for securing the support element to a resectioned femur;[0027]
• FIG. 10 is a front elevation of the clamp device shown in FIG. 9;[0028]
• FIG. 11 is an isometric view of part of the support element;[0029]
• FIG. 12 is a partial side view of an alternative embodiment of the clamp device shown in FIGS. 9 and 10;[0030]
• FIG. 13 is an isometric view of the embodiment shown in FIG. 12;[0031]
• FIG. 14 is an isometric view of the construction shown in FIG. 13 partially dissembled;[0032]
• FIG. 15 is an end view of the device shown in FIG. 11 incorporating the alternative constructions shown in FIGS. 12, 13 and[0033]14 and including visual indicator guides with the support element in a first position;
• FIG. 16 is a similar view to FIG. 15 with the support element in a second aligned position;[0034]
• FIG. 17 is an isometric view showing a drill guide which can be clamped into position to enable holes to be made through the bone and soft tissue when it has been folded back into a position on the femur;[0035]
• FIG. 18 is a front elevation of the clamp as shown in FIG. 10 attached to a drill guide element;[0036]
• FIG. 19 is a plan view from above the drill guide element shown in FIG. 18 in part cross-section on the line V-V of FIG. 19; and[0037]
• FIG. 20 is an end view of the drill guide element shown in FIG. 1.[0038]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• In endofemoral osteotomy surgery the proximal end of the femur is resectioned by removing its proximal end. The stem of the prosthetic implant is inserted into the proximal end of the bone canal and accurately located by the surgeon. The exact position of the femur must be accurately judged and the distal end of the stem of the implant usually carries one or more openings through which one or more retaining bolts are passed. Thus these bolts pass through the bone and the implant to anchor the stem of the prosthesis.[0039]
• It is difficult for surgeons to judge the exact position to drill the holes so as to coincide with the holes in the implant and to select the correct angular position. The position of the holes also controls the corrected leg length.[0040]
• FIG. 1 shows a targeting apparatus for use in performing endofemoral osteotomy surgery and this comprises a support element[0041]1 provided with twodrill guides2 and aconnector3 for securing the support element1 to aprosthesis4 which is to be implanted in a resectioned femur which is indicated byreference numeral6. Anadjuster7 is included for adjusting the angular position of thedrill guides2 in relation to the resectionedfemur6 about a proximal-distal axis.
• The support element[0042]1 is in the form of an L-shaped frame which has afirst arm10 and a second proximal location element provided by a curved arm11. As will be seen from FIGS. 1, 2 and3 curved arm11 is substantially S-shaped. Thusfirst arm10 carriesdrill guides2 and the proximal location element provided by the S-shaped arm11 carriesconnector3 for connecting the support element1 to the proximal end of the femoral prosthesis.
• [0043]Connector3 for connecting support element1 to the femoral prosthesis through the proximal location element provided by the S-shaped arm11 is shown in more detail in FIG. 8 and comprises asleeve20 secured to S-shaped arm11 and in which is located asecuring stud21.
• The[0044]proximal end22 of theprosthesis4 is provided with a screw threadedbore23 in which a screw threadedportion24 of thestud21 can be located. The other end of the stud is held by anut25.
• The distal end of[0045]sleeve20 is provided with a pair ofopposed projecting keys26 which engage inkeyways27 in the form of slots provided in an enlarged end portion ofbore23.
• Thus, it will be seen that[0046]prosthesis4 can be held in position on S-shaped arm11 and be restrained against relative rotation by thekeys26 and thekeyways27.
• Drill guides[0047]2 are carried onarm10 by a clampingplate40 which is held in place by a screw threaded shaft41 which engages ascrew thread42 in the clamping plate. The screw threaded shaft41 passes through a series ofopenings43 inarm10. As will be seen from the drawings, once the guides have been fixed in position there is a predetermined distance from the guides toconnector3 for connecting support element1 to thefemoral prosthesis4. This distance can however be adjusted by usingalternative openings43. Drill guides2 are set for a position with respect to the given prosthesis so that they are fixed and aligned with the holes (not shown in FIGS. 1 and 2) inprosthesis4.
• A[0048]typical drill bit45 is shown in place in one of the drill guides2 and its lower operative end46 (as shown in FIG. 2) indicate how it has been drilled through thefemur6 passing through the existing holes in the stem of the prosthesis and through the other side of thefemur6.
• The proximal location element in the form of the S-shaped arm[0049]11 is detachable from the support element1 and is secured by a plug and socket connection indicated byreference numeral90. Atriangular socket91 is provided inarm10 into which a triangular shapedplug92 is inserted. This construction is more clearly shown in FIG. 7.
• The[0050]plug92 is retained in position by a lockingscrew93 in the end of the arm.
• The proximal location element in the form of the S-shaped arm[0051]11 is shaped to extend around the great trochanter and muscles (indicated byreference numeral94 in FIGS.1 to3) of the femur hip joint in which the implant is to be located. This enables a frame of the type described above to be employed.
• Two S-shaped arms[0052]11 are provided, one for use with a right femur and the other for use with a left femur, the appropriate arm being used.
• To carry out the surgery relating to endofemoral osteotomy the surgeon first ensures that appropriate X-rays have been taken so that he can consider the amount of bone which needs to be removed from the femur. Once this has been decided the measurements are carefully taken for further use with the apparatus according to the invention.[0053]
• The femur is appropriately resectioned and the prosthesis is inserted. It is then connected to the targeting device by means of[0054]connector3 for connecting it to the support element1. With the support element1 now suitably connected it is rotated axially about a proximal-distal axis of the femur until the correct position of the drill guides2 is achieved. They will have been previously set to an appropriate and predetermined position on the proximal-distal axis. A visualindicator guide arm70 is attached to the L-shaped frame in the form of a rod and this can also be employed to achieve the correct position. With the targeting device accurately located the surgeon can drill the requires holes in thefemur6 and this can be done without interfering with themuscle94.
• The targeting apparatus shown in FIGS.[0055]1 to3 can also be employed for performing transfemoral osteotomy surgery by adding additional components.
• In this surgical technique the femur is exposed along a proximal-distal line, the soft tissue (skin, muscle) being folded back on each side to expose the bone. The proximal end of the femur is now opened as a “window” and a femoral prosthesis is inserted into the bone canal.[0056]
• FIGS. 4 and 5 show, in simplified form, how transfemoral osteotomy surgery is performed. The soft tissue indicated by reference letter T in FIG. 5 is exposed along a proximal/distal line indicated by chain line L in FIG. 5. The soft tissue T is folded back on each side to expose the[0057]femur6 and the bone is resected with three cuts along the same line L two side cuts M and with a transverse cut C. The proximal end of the femur is now opened, as shown in FIG. 5, as a “window.” From FIG. 5 it will be seen that anupper quarter48 is now laid on each side of the remaining part of the bone to expose the bone canal into which the prosthesis is to be inserted.
• FIGS. 6 and 7 show how additional or substituted parts are used with the targeting apparatus as shown in FIGS.[0058]1 to3 so that it can be converted for use in performing transfemoral osteotomy surgery.
• In FIGS. 6 and 7 the same reference is used to indicate similar parts to those shown in FIGS.[0059]1 to2 but the S-shaped arm11 is substituted by a substantially straight proximal arm11awhich is provided with the same type of plug andsocket50 andconnector3. Additionally femur connector orclamp5 are provided which are connected to thefirst arm10 by anadjustable bracket12 which can be adjusted in proximal-distal directions only in aslot13 in thearm10 and locked in position by a retainingnut14, and thefemur connector5 can be angularly adjusted in relation tobracket12 in aslot15 provided on the bracket and locked in position by anut16.
• The[0060]nut16 is carried on a screw threaded boss indicated byreference numeral17 is carried on thefemur clamp5.
• Connector or[0061]clamp5 for securing the support element to aresectioned femur6 is most clearly shown in FIGS. 9 and 10 and comprises an open-jawed clamp device. This device has amain body portion30 on which is located amovable clamping jaw31. The upper part of the clampingjaw31 has a screw threaded bore32 which houses a threadedmember33 one end of which carries anoperating handle34 and the other end of which is rotatably housed in thebody30. Thus, rotation of thehandle34 raises and lowers theclamp31 which is also located by a retainingscrew35 which passes through aslot136.
• The lower end of the open jawed clamp is formed as a pair of[0062]curved tines36 which are adapted to extend around the resectioned femur to which the device is to be clamped.
• A guide in the form of a[0063]disc38 mounted onbody30 are provided, the disc projecting below thelower end39 of thebody30.
• The[0064]boss17 is located in aslot40 in thebody30 and held by anut37 but is free to move so that the position of the clamp adjusts itself in relation to theadjustment bracket12 to alter the radial distance from thefemur6.
• In order to clarify the drawings in FIG. 6 the soft tissue T and bone which has been folded back to provide the “window” and expose[0065]femur6 is not shown but the femur will be in the condition shown in FIG. 5.
• To carry out the surgery relating to a transfemoral osteotomy the surgeon first ensures that appropriate X-rays have been taken so that he can consider the amount of bone which needs to be removed from the femur. Once having decided this the measurements are carefully taken for further use with the apparatus according to the invention.[0066]
• The “window” is now opened to reveal the femur and the bone is cut appropriately to provide a proximal end C, indicated by[0067]reference numeral49 in FIG. 5. Theclamp5 is now located in position on the end of the femur by tucking it around the femoral end and ensuring that theguide disc38 is close up against thesevered end49. The positioning is achieved with a rotative movement. Once in place thehandle34 is operated to close the clamp and retain it in place. The stem (not shown) of theprosthesis4 is now inserted in the femoral canal and the frame in the form of thearms10 and11 is connected to it by means of theconnector3.
• The[0068]nut14 is released to allow thebracket12 to move inslot13 and so that it can be secured tofemur clamp5 by theboss17 andnut16 through theslot15. The release ofnut16 allowsslot15 to be placed onboss17 at the appropriate radial distance from the femur prior to subsequent tightening. It will be appreciated that the proximal-distal movement inslot13 accommodates the leg length adjustment. The ante/retroversion (version angle) adjustment is now carried out by revolving the frame about axis of theprosthesis4 and the particular angle adjustment is set by tighteningnut16. During thisangular movement prosthesis4 which is securely attached to the support frame revolves with it as do drill guides2.
• The proximal-distal positioning of the drill guides is set according to the pre-operative planning and they are now positioned by releasing[0069]nut42 so that they can be located in contact with the cortex of the femur and the nut suitably tightened.
• The drill guides can now be used to produce the necessary holes through the bone to accept the required bolts or pins.[0070]
• In the arrangement described above two drill guides are shown but only one or any other number can be utilized if required.[0071]
• The apparatus can be simply removed by releasing the[0072]stud21 inprosthesis4, releasing thenut16 and removing the frame. Theclamp5 can be removed separately.
• The “window” is now closed according to any known post-operative technique.[0073]
• FIG. 11 shows an alternative embodiment in which the same reference numerals are used to indicate similar parts. In this arrangement[0074]adjustable bracket12 can be readily disconnected fromfirst arm10 of the L-shaped frame. In thisconstruction nut14 is shown as a hand nut and is carried on aboss50 which has abore51 adapted to receive aspigot52 provided on the end of thebracket12.Boss50 also carries a screw threaded lockingnut53 which can be advanced through a screw threaded bore (not shown) so that it engages against thespigot52 where it is located inbore51 to clamp it in position. This construction enables disconnection of the assembly without having to unscrew lockingnut14 thus enabling the leg length to be set without readjustment.
• FIGS. 12, 13 and[0075]14 show an embodiment construction for the open jawed clamp device and the same reference numerals are used to indicate similar parts to those shown in FIGS. 9 and 10. In this embodiment however, theboss17 is replaced by abolt60 which extends through theslot40 and carries a spacer61. Oneend62 of the spacer is dished to accommodate a part-sphericallyshaped washer62. A second part spherically-shapedwasher64 is also located on thescrew60 and one side of this is housed in a dishedportion65 of thenut66. Thenut66 has acircumferential groove67 to accommodate resilient ring (not shown) which can act to retain a socket wrench during assembly. Each of thewashers64 and63 also has a flat side which are located against the sides ofslot15 onbracket12 when the whole construction is assembled together withscrew60 passing through theslot15.
• With[0076]nut66 tightened, the assembly is tightly clamped together, but if thenut66 is slackened thebracket12 can align itself in three different directions by a movement of the part spherical washers in thespacers61 and65. This enables three relative rotations, one of which is the anteversion setting on the other two rotations enable centering of the stem in the femur if the clamp is ill positioned on it.
• As the attachment of the clamp to[0077]bracket12 is also adjustable and can be clamped in position movement of the clamp in the direction of thearrows68 on FIG. 13. This enables the automatic adoption of the femur diameter and once set can be tightly adjusted to provide rigidity of the assembly.
• FIG. 15 shows how visual indicator guides can be provided. Thus, a visual[0078]indicator guide arm70 is attached to the L-shapedframe10 in the form of a rod which extends at150 to the axis of thefirst arm10. A second indicator guide71 which is also in the form of a rod is attached at an angle normal to the longitudinal axis of the clampmain body portion30.
• Using the visual indicator guides the apparatus is placed in position with the clamp positioned perpendicular to the 90° knee flexion plane. This is the first position of the anteversion at 0° and this is shown in FIG. 15. In FIG. 16 the L-shaped[0079]frame10 has been rotated until the visual indicator guides70,71 are parallel. In this position theframe10 has been rotated through 15° in relation to theclamp30. Thus, the neck axis is parallel to the axis of theframe10 and the rotation of the frame has thus created an angle between the clamp and the frame which is the anteversion angle. The exact angle of anteversion can be read from a scale indicated byreference numeral72 provided on thebracket12.
• The standard value of anteversion is 15° and this can be used as a datum when setting up the apparatus.[0080]
• When the “window” is closed it is necessary to fold the soft tissue and bone which has previously been folded back to provide the window back into position and locate it around the installed prosthesis. FIG. 17 shows how a[0081]proximal drill guide75 can be provided to guide drills through the folded back “flap” and to enable the drills to line up withpre-arranged holes76 provided on theprosthesis4. This device is in the form of an open jawed clamping block77 which is provided with a tighteningscrew78 which passes through a threaded bore (not shown) in the block to extend into thegap79 provided between alower clamping jaw80 and an upper clamping jaw81. The clamping block77 carries an arm82 which supports a pair of drill guides83.
• As will be seen from FIG. 17 the prosthesis is provided with a series of[0082]openings76. With the prosthesis in support element1 and held by second arm11 the clamping block is placed in position and the drill guides are aligned by the use of guide rods or drills84. With the drill guides now aligned withopenings76, the clampingscrew78 is tightened to lock the clamping block in position. The rods or drills84 can now be removed, the “window” is closed and the drill guides employed to guide the drill or drills to make openings in the flap of bone andsoft tissue48. The openings can then be located by passing wire hoops through the openings and suitably locating them thus ensuring that the flap of material is held in place.
• FIGS. 18, 19 and[0083]20 show apparatus for carrying out the first part of the transfemoral osteotomy surgery as shown in FIGS. 1 and 2 and utilizes the clamp device shown in FIGS. 9 and 10 for securing the support element to a resectioned femur. The apparatus includes adrill guide element100 which is rigidly secured to thefemur6 by the open jawed clamp device which has aboss17 located in aslot40 in thebody30 and is held bynut37 so that the position of thedrill guide element100 can be adjusted to alter the radial distance from thefemur6.
• The[0084]drill guide element100 comprises asemi-circular support101 connected to alocation bracket102. Thisbracket102 has aslot103 through which the end of theboss17 can extend, the bracket being held in position by thenut16.
• The surface of the[0085]bracket102 is marked withgraduations104 to indicate the relative angular position between the two parts.
• The[0086]drill guide element100 includes a line ofdrill openings106 along each side and which are adapted to guide a drill, the line of openings extending in a proximal/distal direction. Two parallel lines of drill openings are provided.
• [0087]Adjacent drill openings106 are angled in relation to each other as will be seen from FIG. 19 each of the entry points107 on the outer side of the element serves three openings on the inner side of the element so that there are more entry points or openings on the inner side of the element than there are on the outer side. This enables a row of closely spaced openings to be drilled on each side.
• A guide for guiding the instrument for exposing the femur along a proximal/distal line is also provided in the form of a[0088]guide slot110 through which the surgeon can open soft tissue and subsequently saw the first longitudinally extending cut in thebone6 after it has been previously transversely cut.
• The apparatus is used for resectioning a femur when performing transfemoral osteotomy in the following manner. The surgeon first makes a transverse cut C to expose a proximal end of the femur which can be used as a reference point. This reference point end is exposed by the surgeon and the means for securing the drill guide element to the femur, that is the clamp, is placed in position by sliding the[0089]tines36 around the bone ensuring that theguide disc38 is close up against the severed end indicated byreference numeral49. As mentioned above, the positioning is achieved with a rotative movement. Once in place thehandle34 is operated to close the clamp and maintain it in place. Thedrill guide element100 is now placed and locked in position bynut16. The element extends over the femur and the surgeon now opens the upper part of the femur by severing the soft tissue through theslot101. This exposes the femur beneath it so that the surgeon can cut a proximal/laterally extending slot. The surgeon now drills a series of holes using the drill guide means through the soft tissue and into the bone. The row of holes in the bone provides a row of perforations which can be easily broken away to provide the side cuts M but leaving the two broken away parts of the bone still attached to the remainder by the soft tissue in the manner shown in FIG. 5.
• The “window” now obtained can be used for the remainder of the operation and leaves the femur ready to receive the prosthesis.[0090]
• Prior to opening the bone the[0091]drill guide element100 will, of course, have been removed by releasing thenut16 but the connector in the form of the clamp can be left in position. The same clamp is now used during the remainder of the operation to act as a connector for securing a support element provided with a drill guide to a prosthesis to be implanted and to a resectioned femur, and an adjuster for adjusting the angular position of the drill guide in relation to the resectioned femur about a proximal/distal axis as explained above.
• The drill guide element can be used with the clamp in place on the targeting apparatus but if desired it can be removed and used separately with the[0092]drill guide element100 as described above.
• The targeting apparatus according to the invention provides a modular construction which includes a support element with a drill guide, a connector for securing it to a prosthesis, an alternative connector for securing it to the prosthesis, a clamp for securing it to the femur, a drill guide for drilling holes in the proximal end of the prosthesis and a drill guide for drilling a line of openings in the proximal-distal direction when preparing the “window” when performing transfemoral osteotomy surgery. The modular construction allows the various parts to be assembled together as required. Alternatively only some of the apparatus is required when performing endofemoral osteotomy surgery. When supplied as a complete kit the various parts can be assembled together as required at the time.[0093]
• Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.[0094]

Claims (47)

1. A targeting apparatus for use in performing endofemoral osteotomy surgery comprising a support element provided with a drill guide, means for securing the support element to the proximal end of a prosthesis to be implanted and which include a proximal location element which is shaped to extend around the great trochanter and muscles of the femur in which the implant is to be located, and means for adjusting the angular position of the drill guide in relation to the femur about a proximal-distal axis.

2. The targeting apparatus as claimed inclaim 1 wherein the proximal location element is in the form of a curved arm connected to the support element.

3. The targeting apparatus as claimed inclaim 2 wherein the curved arm is substantially S-shaped.

4. The targeting apparatus as claimed inclaim 1 wherein the proximal location element is detachable from the support element.

5. The targeting apparatus as claimed inclaim 4 wherein the proximal location element is attached to the support element by a plug and socket connection.

6. The targeting apparatus as claimed inclaim 5 wherein the plug is of triangular cross-section.

7. The targeting apparatus as claimed inclaim 4 wherein the apparatus includes two detachable alternative proximal location elements, one for use with a right femur and the other for use with a left femur.

8. The targeting apparatus as claimed inclaim 1 further comprising means for adjusting the support element to accommodate alternative leg lengths.

9. The targeting apparatus as claimed inclaim 8 in which the drill guide is located at a predetermined proximal-distal position from the means for connection to the proximal end of the femoral prosthesis.

10. The targeting apparatus as claimed inclaim 8 further comprising means for locating the drill guide in alternative proximal-distal positions on the support element.

11. The targeting apparatus as claimed inclaim 1 in which at least two drill guides are provided.

12. The targeting apparatus as claimed inclaim 1 wherein the support element is in the form of an L-shaped frame, one arm of which carries the drill guide and the other arm providing the proximal location element.

13. The targeting apparatus as claimed inclaim 12 wherein the conversation means includes means for securing the support element to a resectioned femur.

14. The targeting apparatus as claimed inclaim 1 further comprising conversion means for converting it for use in performing transfemoral osteotomy surgery.

15. The targeting apparatus as claimed inclaim 14 further comprising alternative means for securing the support element to the prosthesis to be implanted and which is adapted to replace the shaped proximal location element.

16. The targeting apparatus as claimed inclaim 15 wherein the said alternative means comprise substantially straight proximal arm adapted for connection to the support element.

17. The targeting apparatus as claimed inclaim 10 further comprising means to indicate the angular position of the drill guide relative to the resectioned femur.

18. The targeting apparatus as claimed inclaim 14 further comprising means to vary the proximal-distal position of the support element in relation to the prosthesis securing means.

19. The targeting apparatus as claimed inclaim 14 wherein the means for securing the support element to the resectioned femur is in the form of an adjustable open jawed clamp adapted to partially surround the femur with which it is to be used.

20. The targeting apparatus as claimed inclaim 14 further comprising guide means for locating the resectioned proximal end of the femur.

21. The targeting apparatus as claimed inclaim 20 wherein said guide means are carried on the femur securing means.

22. The targeting apparatus as claimed inclaim 13 wherein the securing means are connected to the L-shaped frame by an adjustable bracket which can be adjusted in proximal-distal directions on the frame and in relation to which the femur securing means can be angularly adjusted about a proximal-distal axis.

23. The targeting apparatus as claimed inclaim 22 in which said adjustable bracket is readily removeable from the L-shaped frame.

24. The targeting apparatus as claimed inclaim 14 wherein the femur securing means includes means for adjusting and clamping the securing means according to the femur diameter.

25. The targeting apparatus as claimed inclaim 14 wherein the means for securing the support element to the resectioned femur includes a universal joint.

26. The targeting apparatus as claimed inclaim 13 further comprising a drill guide for drilling openings through the bone and soft tissue when it has been folded back into position at the proximal end of the femur.

27. The targeting apparatus as claimed inclaim 13 further comprising a drill guide element which has a line of drill openings each of which is adapted to guide a drill and means for rigidly securing said drill guide element to a femur to be resectioned with the line of openings extending in a proximal/distal direction.

28. The targeting apparatus as claimed inclaim 27 further comprising means for altering the angular position of the drill guide element on the femur about a proximal/distal axis after it has been secured thereto.

29. The targeting apparatus as claimed inclaim 27 wherein the drill guide element includes two parallel lines of drill openings.

30. The targeting apparatus as claimed inclaim 27 wherein adjacent drill openings are angled in relation to each other so that the openings are more closely spaced apart on the outer side of the element than on the inner side adjacent the femur.

31. The targeting apparatus as claimed inclaim 30 wherein each of the entry points of the openings on the outer side of the element serves two or more openings so that there are more entry points for openings on the inner side of the element than on the outer side.

32. The targeting apparatus as claimed inclaim 27 wherein the drill guide element also includes means for guiding means for exposing the femur along a proximal/distal line.

33. The targeting apparatus as claimed inclaim 32 wherein the guiding means is in the form of a guide slot.

34. The targeting apparatus as claimed inclaim 27 wherein the drill guide element is removably connected to the securing means.

35. The targeting apparatus as claimed inclaim 27 wherein the means for securing the element to the femur is said adjustable open jawed clamp adapted to partially surround the femur with which it is to be used.

36. The targeting apparatus as claimed inclaim 27 further comprising means for locating the securing means on a partially resectioned transverse end of the femur after the first transverse cut has been made.

37. A kit of parts to provide targeting apparatus for use in performing endofemoral and/or transfemoral osteotomy surgery comprising:

a support element provided with a drill guide, means for securing the support element to a prosthesis to be implanted when performing transfemoral surgery, means for adjusting the angular position of the drill guide in relation to the resectioned femur about a proximal/distal axis, and means for securing the support element to a femur.

38. The kit of parts as claimed inclaim 37 further comprising a drill guide element which has a line of drill guide openings each of which is adapted to guide a drill and means for securing said drill guide element to the said means for securing the support element to a femur.

39. The kit of parts as claimed inclaim 37 further comprising a drill guide for drilling openings through the bone and soft tissue when it has been folded back into position at the proximal end of the femur when conducting transfemoral surgery.

40. A targeting apparatus for use in implanting a prosthetic femoral component having through holes for receiving screws extending transverse to a longitudinal axis of the femur, comprising:

a first arm extending generally parallel to the longitudinal axis of the femur, said first arm having at least one drill guide thereon; and

a second arm supported by said first arm, said second arm coupled to a proximal portion of said femoral component and shaped to extend around the greater trochanter and muscles of the hip joint.

41. The targeting apparatus as set forth inclaim 40 wherein the first arm is adjustable in length.

42. The targeting apparatus as set forth inclaim 40 further comprising a clamp support by said first arm for clamping on the femur.

43. The targeting apparatus as set forth inclaim 42 wherein said clamp is supported on said first arm in a manner permitting adjustment along the longitudinal extend thereof.

44. The targeting apparatus as set forth inclaim 43 wherein said clamp is slidably mounted on a longitudinal extending guide track formed on said first arm.

45. The targeting apparatus as set forth inclaim 40 wherein said second arm is curved.

46. The targeting apparatus as set forth inclaim 45 wherein said second arm is S-shaped.

47. The targeting apparatus as set forth inclaim 40 wherein said second arm is coupled to a proximal end of the femur by a connector threadably engaging a threaded bore in the proximal end surface of the femoral component.

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